Cyclocross and Gravelbiking (Recreational)This has to be the most physically intense sport ever invented. It's high speed bicycle racing on a short off road course or riding the off pavement rides on gravel like :The Dirty Kanza". We also have a dedicated Racing forum for the Cyclocross Hard Core Racers.

I'm seriously looking at the Cannondale Cyclocross. I think it's a solid bike. I will use it for serious road miles, some hills, commuting, and occasionally off road. Being a little uninformed about this new dimension in cycling, the double ring troubles me. It has a 38/46 double ring; SRAM P950, 12-26 on the back end. Will I get a real workout if I take it for some serious roadwork? (Most road bikes come with a triple, 52 being top end.) What about hills? Will I need the smaller third ring? I'm about to drop $1000 on sale. If a real road workout and solid frame is what I'm looking for, is this a good choice?

I haven't encountered a hill that I couldn't handle with my 38/48 chainrings and 12/32 cogset. I would keep the double, as it has less troublesome shifting than the triples I've had, and get a 12/32 or even a 12/34 cassette.

It has a 38/46 double ring; SRAM P950, 12-26 on the back end. Will I get a real workout if I take it for some serious roadwork? (Most road bikes come with a triple, 52 being top end.)

As others have mentioned, you'll do fine with the double ring. You have plenty of range there. As a matter of fact, most roadbikes are doubles, not triples. You'll find that the 38/26 to be plenty low enough for most hills... Nice bike, BTW....

agreed. imo keep the double. I've battled this before. I have a touring bike w/ a triple and 12 -32 cassette. triple is good w/ a fully loaded bike but even so if you look at a gear chart you will see you can get most gear ratios with a double that you can with a standard triple provided it is set up properly of course. My new ride has a double 53/39 and 12-27. I have'nt tested it yet on the big hills but if it is too much then I will get a compact crankset for probably 200 USD or so which is cheaper than a triple conversion and easier to swap out for crits or if I move to Kansas You may find you want a 52 up front though if your on the road a lot for the other side of the hills...

Keep the double for sure. The 38/26 should be fine for all but the steepest of hills, and 48/12 should be ok for top speed too. It's very easy to switch up to a 50 or a 53 if you find the 48 too small. I've seen this bike at my LBS and it looks very strong and durable, I'd quite like one, especially the disk brake version, but they don't have rack/fender mounts

I have a gear inch calculator which is the only real way to figure this out...

With a 38/46 front rings, and a 12-26 cassette in the back, you would
have (assuming 700x30 tires):

lowest gear inches: 39
highest gear inches: 103

As a comparison, with a road triple crankset (52/42/30), you would
have:

lowest gear inches: 31
highest gear inches: 116

With a mountain triple crankset (44/32/22), you would have:

lowest gear inches: 23
highest gear inches: 99

It's probably not as good an idea to use a wide range cassette (i.e. 11-34) in the rear due to the large jumps between shifts (especially for road riding where maintaining cadence is important).

Some side notes:

o 100 gear inches is tall enough on the top end except for pedaling down hills at speeds in excess of about 25-30 mph.

o 39 gear inches is short enough on the climbing end for hills about 8-10% grade, not much steeper than that. Hills in the 10-12% range will wear you out quickly. And anything steeper will be really tough on your knees. Of course a lot depends on your strength and climbing efficiency.

o Most road hills generally do not exceed 15% (this is very steep), although there are some as extreme as 24%. However off-road trails can be easily be in that range.

With my 38/46, 700c/35, 11-32, 170mm crank setup my gears range from 32.3 to 113.6. With my 22lb bike, I make it up some fairly steep hills with my 10lbs of backpack on too.
I haven't needed very close ratio of gears either. For some reason I always like to feel a difference in effort when I downshift so I usually shift two gears at a time when I hit the hill anyway. YMMV

[SIZE=7][FONT=Arial]I got a new Cannondale XR800 last Oct. Have fitted studdet tires on it, but had to put it back into winter storage and get my old MTB back out as the derailleurs started giving me trouble. Could be easy to fix, but with minus 10 C I am waiting for warmer days before I work on it. Anyone else with same experience?